What’s the real story on seed oils?

 

 

CHICAGO, June 30, 2025 — The nation’s leading health officer has demonized it as a dire threat to American health. Scientists and nutritionists counter that it’s been a wellness breakthrough for a nation that loves its fried foods. 

 

So what’s the real story on seed oils, the fats universally used today in the food-away-from-home business? 

 

The question was front-and-center during this month’s Chefs Culinary Conference at the University of Massachusetts’ Amherst campus. The 700 or so attendees learned the crusade against frying media like canola, corn or soy oils is irrefutably not supported by science, even if the Trump Administration’s Make America Healthy Again campaign is widely expected to stigmatize it as a near poison. 

 

Dr. Walter Willett, one of the world’s leading authorities on nutrition, voiced astonishment that seed oils are even under attack by some public health advocates, including U.S. Secretary of Health & Human Services Robert F. Kennedy, Jr. 

 

“You would think that seed oils are toxic and unhealthy for us,” remarked Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health. Yet, he stressed, the scientific literature on frying media like soy, canola, corn and sunflower oils shows irrefutably that the fats are preferable from a health standpoint to animal-based substances like beef tallow. Indeed, “seed oils are good for us,” Willett asserted. 

 

Plant-oil opponents contend the fats tend to trigger tissue inflammation, particularly among children who consume them, and that can lead to serious health impairments. Yet the scientific evidence indicates “seed oils are not pro-inflammatory,” said Willett. “In fact, about half the literature shows that seed oils are anti-inflammatory.” 

 

His assertions were echoed by Eric Decker, the head of UMass-Amherst's Department of Food Science. As he explained, the science and nutrition communities have little problem with seed oils. The main resistance, he said, is coming from self-anointed public health advocates who’ve convinced Kennedy the oils are a threat.  

 

He spoke a matter of days before Louisiana Gov. Jeff Landry signed a bill into law that requires restaurants in the state to alert patrons if seed oils are used. 

 

Decker also noted that the opponents are ignoring practicality in their crusade against seed oils. Among the most-cited alternatives are “fruit oils” squeezed from sources like olives and avocados. Decker noted that olive oil, likely the least expensive of the alternative choices, currently costs about $54 a quart, compared with the $9 to $11 price of most seed oils. 

 

The higher price doesn’t bring more health benefits, he added. “Canola oil can be healthier than avocado oil,” the fruit oil currently in vogue, said Decker.  

 

He ticked through seed oil opponents’ main objections to those current frying staples.  

 

The oils aren’t produced by squeezing the seeds, as olives or avocados are pressed, Decker explained. A man-made solvent called Hexane is used to extract the fat, and the chemical has been identified as a potential health hazard.  

 

That’s why a number of other nation’s have set limits on its use, he continued. The U.S. has not set similar standards. 

 

But, Decker continued, there’s little data on how much residual Hexane is left in seed oils, and the scientific literature indicates it’s not very toxic in any case. 

 

Opponents also allege the extraction process destroys seed oils’ nutritional value. “That’s not true,” Decker stated, citing scientific evidence.  

 

But the data does show that seed oils don’t pack many of the health detriments that are evident in beef tallow, the frying medium Kennedy champions as preferable. That medium abounds in saturated fats, the sort that tends to clog arteries.  

 

Decker, Willett, and a number of other speakers pointed out that beef tallow was the frying staple for restaurants and food processors several decades ago. But concerns about its health detriments prompted the food-away-from-home industry to adopt seed oils in its place, a move championed at the time as a major step in improving Americans’ diet. 

 

Decker also addressed the assertions of Kennedy and other advocates that seed oils foster inflammation in humans. The dynamic they cite is an imbalance in the two types of fatty acids that constitute seed oils, Omega-6 and Omega-3. A high ratio of the former to the latter is what can trigger inflammation, and seed oils opponents say the ratio for seed oils is a patent hazard. 

 

But, he stressed, that assertion "does not have much credibility.” The opponents are overstating the presence of Omega-6, he explained. 

 

Decker seemed exasperated by an ongoing debate that is already prompting FAFH operations to choose sides. The Sweetgreen fast-casual chain introduced a seed-oil-free menu in January, with avocado and olive oils used in place of the usual shortenings.  

 

In February, the Steak ‘n Shake family dining chain won praise from Kennedy by changing out its vegetable-based frying oil with 100% beef tallow.  

 

“The recommendation that no one mentions,” concluded Decker, “is,you should just eat less fried food. This is not so controversial, and could lead to greater health.” 

 

The Chef Culinary Conference drew about 700 chefs and foodservice directors from college and university dining programs from across the country.  

 

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